NF1 and neoplasm: NF1 is caused by heterozygous mutations of the NF1 gene (chromosome 17q11.2) which contains 57 constitutive and 3 alternatively spliced exons3 and encodes neurofibromin, a protein with tumor suppressor function, ubiquitously expressed and involved in pathways affecting cell growth and development of skeletal, cardiovascular, and nervous systems4.